1. Field of the Invention
The present invention generally relates to a motor and a cooling fan utilizing the motor and, more particularly, to a motor with better heat dissipation efficiency and a cooling fan utilizing the motor.
2. Description of the Related Art
Referring to FIG. 1, a conventional motor 9 including a first housing 91, a second housing 92, a stator 93, a rotor 94 and a circuit board 95 is shown. The first housing 91 includes a compartment 911 having an opening. The second housing 92 is located on the opening of the compartment 911. The stator 93 is received in the compartment 911. The rotor 94 rotatably extends through the second housing 92 to be fixed in a center of the stator 93. The circuit board 95 has one face abutting with a shoulder portion 921 of the second housing 92 and another face abutted and pressed by a covering plate 922. Since the covering plate 922 is made of a metal material, an insulation board 96 is required to be disposed between the covering plate 922 and the circuit board 95 to prevent the circuit board 95 from being short-circuited. In the motor shown in FIG. 1, the circuit board 95 is electrically connected to the stator 93, enabling the circuit board 95 to control the stator 93 for triggering rotation of the rotor 94.
During operation of the motor 9, some parts of the motor 9 such as the stator 93, electronic components 951 on the circuit board 95 and bearings 97, will have increasing temperature during operation of the motor 9. Therefore, two air rooms are designed on two sides of the circuit board 95, enabling heat generated by the electronic components 951 to be dissipated into the air rooms. The heat in the air rooms then experiences heat exchange with external air through the covering plate 922 by ways of air convection or thermal conduction, thus cooling the temperature in the motor 9.
However, since the circuit board 95 is separated from the covering plate 922 by the insulation board 96 made of an insulation material with low thermal conductivity such as polyvinyl chloride or polystyrene, the insulation board 96 is not able to efficiently guide the heat to the covering plate 922 for heat exchange. In this case, the hot air in the motor 9 can only have heat exchange with the external air by way of air convection, leading to low heat dissipation efficiency of the motor 9. Thus, the motor 9 will have shorter service life or even breaks down. Therefore, it is desired to improve the conventional motor 9.